Meter



Jan. 14, 1930. T. R. HARRISON 1,743,852

' METER Original Filed Dec. 29, 1925 2 Sheets-Sheet 1 MERCURY rail 21WATTORNEY V Original Filed Dec. 29, 1925 2 Sheets-Sheet 2 INVENTOR7/70Mfl5 1?. fur/7x50 r BY ATTORNEY Patented Jan. 14, 1930:

' UNITED STATES PATENT; OFFICE THOMAS E. HARRISON, OF PHILADELPHIA,PENNSYLVANIA, ASSIGNOB TO THE BROWN INSTRUMENT COMPANY, OF PHILADELPHIA,PENNSYLVANIA, A CORPORA- TION 0F IENNSYLVANIA Original application filedDecember 29, 1925, Serial No. 78,148. Divided and this application filedMay 3,

1928. Serial No. 108,346.

The general object of the present invention is to provide. an improvedmeter mechanism particularly devised and adapted for determining therate of flow of fluid through a conduit from a pressure diilerentialwhich is a function of said rate of flow. A more specific object of theinvention is to provide imcharacterizedby their mechanical andelectrical simplicity and reliability, and their operation moreover, issubstantially independent of minor variations in the voltage of thesource of energizing current employed, so that such source may be anordinary alternating current power or lighting circuit, and no currentregulator or the like is required to compensate or correct "for suchvoltage fluctuations as ordinarily occur in such a circuit.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,however, its advantages and specific objects attained with its use,reference should be had to the accompanying drawings and descriptivematter in which Lhave illustrated and described preferred embodiments ofmy invention.

Of the drawings:

Fig. 1 is a somewhat diagrammatic representation of a flow meter with;parts broken away and in section;

Flg. 2 is a diagrammatic representation of a modified construction; and

Fig. 3 is a perspective view of a portion of the apparatus shown in Fig.2.

My improved instrument in the form shown in the drawings, comprises anindicating, recording and integrating portion collectively designated bythe symbol G, and an actuator which is a diderential pressure device A,when the instrument, as in the form shown, is. intended formeasuringfluid rate of flow. The diderential. pressure device A, as shown,comprises a casing body which may be described as cup-shaped and whichhas its interior divided into two chambers A and A byFa suitablepartition wall. The latter, as shown, is formed by a cupshaped part(1,0f sheet metal comprising a vertically disposed cylindrical bodyportion which surrounds the chamber A. The part a has an out-turnedflange at its open upper end which is clamped against the upper end ofthe casing body by a clamping head A and said flange closes the upperend of the chamber A? which surrounds and extends beneath the lowor endof the chamber A. Advantageously,

as shown, the lower portion of chamber A is enlarged to hold asufficiently large quantity of a suitable sealing liquid B. Theparticular liquid B employed will vary with the conditions of use andfor many purposes may well be mercury. The chambers A and A may be infree communication at their lower ends, but as shown they are incommunication through a restricted orifice a formed in the otherwiseclosed bottom of the member a. Y

In the useof the apparatus to measure the flow of a fluid through aconduit C, the chamhers A and A are connected by pipes D and D,respectively, to the conduit C at points thereof between which there isa difference of pressure which is a function of the fluid rate of .fiowthrough the conduit. As shown, the

pipe D connects the chamber A to theconduit C at the down-flow or outletside of a restr cted orifice C in the conduit C, while the pipe Dconnects the chamber A to the conduit C i square root of the change invelocity or volume of flow through the orifice C. As this pressurediilerence increases, the 'seallng liquid is transferred from thechamber A to the chamber A through the orifice a, and

thereby gives movement to a float E resting on the sealin liquid in thechamber A. The movement the float E thus produced gives correspondingmovements to an electro-magnetic core body E supported by the float Ethrough a connecting stem part. The-core is movably received in andguided by a casing member A of non-magnetic metal and shown as a tubularpart having its upper end closed and havin its lower open end secured inan a erture :tormed for the purpose in the c amping head A which withthe art A closes the upper end of the chamber KC.

Ihe indicating recording and integrating section G of the instrumentcomprises a vertically movable magnetic core 6 to which the movementsor" the core E are transmitted by electro-magnetic means. ihe iastmentioned means in the preferred construction illustrated, compriseswhat I call an impedance the core 6 and so connected into the impedancebridge that when the movement of the core E unbalances the impedancebrid e by varying the inductance of the coil F re ative to that of thecoil F, the electro-magnetic interaction between the core e and thecoils f and i will move the core e downward or upward accordingly as themovement of the core E is upward or downward, respectively, as requiredto re-balancethe impedance bridge.

To this end the coils F andF are connected in series between alternatingcurrent supply conductors 1 and 2 as by conductors 3,4, and 5. The coilsf and f are similarly connected in series between the conductors l and 2by branches 30 and 50, respectively, from the conductors 3, and 5, andby a conductor, 40, and are so relatively wound and connected betweenthe supply conductors 1 and 2 that the two coils are energized in thesame direction.

' By'the expression energized in the same direction as used above, andas hereinafter used in the claims, I mean that, disregarding the effectsof such minor differences in phase as may occur, the magnetic lines offorce simultaneously generated by the current flow through the two coilsf and f, pass in the same axial direction through the coil by which theyare generated, so that the magnetic poles created at the remote ends ofthe two coils are of opposite'polarity, as are the poles created' atthe-adjacentends of the coils. The

energiaation in the same direction of the coils F and F is desirablebut, generally speakgreases ing,is less important in the case of thosecoils than in the case of the receiver coils f and f.

The conductors 4 and 40 are directly connected by a conductor 41. Withthis arrangement the coils F and f are connected in parallel with oneanother between the supply conductor 1 and the conductor 41, while thecoils F and f are connected in parallel with one another between theconductor 41 and supply conductor 2.

With the described circuit connections, when the core E moves upward inresponse to an increase in the rate of fiowthrough the conduit C, theinductance of the coil F is increased and the inductance of the coil Fis decreased. This results in a decrease in'the current flow through thecoils F and f and an increase in the current flow through the coils Fand f. With the core e balanced against the action of gravity as itshould be, the increase of current flow in the coil f relative to thecurrent flow in the coil f moves the core e downwarduntil the opposingelectro-magneticinteractions between the core e and coils f and f areequal to one another in intensity. This condition is reached when theratio of the inductances of the coils f and f becomes equal to the ratiobetween the inductances of the coils F and F and the impedance bridge isthereby rebalanced. Similarly, 'on any other movement of the core Ethere is a corresponding movement of the core 6 which thus moves downand up in proportion to the 'up and down movements of the core E. r

In the use of the apparatus shown as a steam fiow meter, the "pipeconnections D and D and the otherwise unoccupied space in the device A,are normally filled with water I of condensation b. To prevent oxidationof the core E, the space in the latter not oc- A, a vent and oil fillingopening A may be provided at the top of the tube A this opening beingclosed by a screw plug A in the normal use of the apparatus.

The indicating recording and integrating section G of the instrumentcomprises a supporting framework in which is mounted a rock shaft Hconnected to, and oscillated by the up and down movement of the core e.The connections shown for this purpose comprise a bell crank iever Kwhich is pivotally supported on the instrument framework K and has onearm connected to the core 0 the parts carried b and has its other armlink-connected to an arm H carried by the rock shaft H. K is acounter-weight by which the moving system comprising the core a, rockshaft H,

the latter, and the connections between it and the core e, are balancedagainst the activity of gravity. Mounted in the instrument framework isa rotatable shaft J carr ing a disk J against the front side of whic apaper record chart J is secured. The shaft J is rotated at a constantspeed in any usual and suitable manner as by means of the electric clockmotor L mounted on the instrument framework and connected to the shaft Jby gearing which need not be illustrated and described. its front endthe rock shaft H carries an arm H bent about the ed "e of the disk J'andprovided in front of t e latter with a stud shaft H co-axiai' with theshaft H, and to which is secured a recording arm J tracing a record onthe chart'd and indicating pointer i which moves along a stationaryscale I when the shaft is oscillated, Theconnection of the recording arm5 and the pointer l to the shaft ll through the co-anial stud shaft Hfacilitate such angular adjustments of the arm and pointer relative tothe shaft H as may be necessary in the calibration of the instrument.

With the simple mechanism already described, the variations in the rateof flow through the conduit C are accurately indicated and recorded.Since, as already explained, the rate of flow through the orifice G isapproximately proportional to the square root oi the difierence betweenthe pressures at the opposite sides of the orifice C, equal incrementsor decrements in the rate offiow will not produce equal movements of thepointer I and recording arm J in different portions of their respectiveranges of movement, so that it is necessary for the scale marks I to beof the general character illustrated with the particular forms of themagnetic cores, the coils, and the chamber A'shown. -Those skilled inthe art will understand, however, that by suitable changes in therelative shapes of the core parts E and e, the coils F, F, and f and for in the shape of'the chamber A, equal changes in the rate of fiowthrough the conduit C may be caused to produce the same angularmovements of the rock shaft H whether the actual rate of flow throughthe conduit C is large or small. The electro-magnetic means provided fortransmitting the movements of the float E to the rock shaft H, operateto make the potential drop in the coils F and f equal to one another andhence to equalize the potential drops in the coils F and f, and theoperationis not afiected by such changes in voltage between the supplyconductors 1 and 2 as may occur in ordinary power and light circuits.

Advantageously, the meter section G may comprise suitable integratingmechanism, and, as shown, the rock shaft H carries an arm S which formsthe measuring element proper of a novel integrating mechanism devised byme. This integrating mechanism need not be illustrated or described indetail herein, however, as its special characteristics form no part ofthe invention claimed herein, and it'is fully described and claimed inmy prior application Serial No. 7 8,148, filed December 29, 1925, ofwhich the present application is a division.

The flow meter disclosed herein possesses impor ant practicaladvantages. The construction is simple, sturdy, and reliable-inoperation. Frictional resistance to the movement of its movable parts isreduced to a minimum especially as no movable parts of the mechanismpass through the walls of pressure chambers so that no frictionproducing stufiing box provisions are required. The total absence ofelectrical contacts engaging and separating as flow conditions change aswell as of stufi'mg boxes frees the instrument from a tendency of movingparts to stick, which interferes appreciably with the attainment of thedesired accuracy and sensitiveness of types of flow meters now in useand avoids all disturbing efiects from var'iable contact resistance. Thefixed positions of the impedance bridge coils and the simple straightmovements of the magnetic core bodies E and 6 reduces lost motion andtrictional resistance to a negligible minimum, and makes the action ofthe apparatus very definite and positive and at the same time assensitive as may be desirable.

The fact that all electrical wires and wind ings are external to themanometer chamber which ma contain water or other materials undesirab yefi'ecting the conductors, eliminates a frequent cause of electricalleakage, short circuits, and burned-out windings, in prior instrumentsin which conductors extend through the manometer walls, and alsoeliminates the necessity for pressure tight bushings for such conductorsrequired in such prior instruments. The non-magnetic tube A whichisadvantageousl made of material of relatively high resistance andrelatively immune to the corrosive action of water or other materialenclosed by it, may readily be made mechanically strong to resist thehigh internal pressures which are experienced in some uses of theinvention. The fact that the tube A may readily be made of materialwhich is not only non-magnetic but also of high electrical resistance,makes it possible to secure the desired inter-action between the core Eand the coils F and F without magnetic shielding by the tube, andwithout requiring the longitudinally slitting of the tube or otherprecautions to prevent undesirably large induced currents in the tubewalls.

The coils and F, f and f, with their connections and the cores E and econstitute a self balancin inductance bridge; i. e., an inductancebridge in which, through the agency of forces inherent in the bridgeitself when the latter is operatively energized, the bridge maintainsitself in a condition of balance core E are practically unailected bysuch 'slight'variations in-the voltage impressed on the impedancecircuit as may be expected in ordinary power or light circuit from whichthe impedance bridge may be energized. The

manner in which the indicating pointer I and recording arm .3 aremountedand arranged avoids all 'bilities of. one interfering with the other andlends itself to the use of an illuminated scale and recording dial andof a broad black pointer so that the instrument indications can beeasily readfrom-- some distance. Furthermore, the scale I ,may be ofample length and still have its numerals verticall disposed totherebyfacilitate meter rea :Erom-a distance.

- the latter, are

Calibration of the meter shown in Fig. 1

is facilitated by an arrangement of the windings F and F, f and f, andcores E e, so that in the balanced condition of the meter in which thereis no current flow through the conductor 41, each core floats, so tospeak, so. that it may be moved axiall of the-surrounding coils by arelafively minute force, while I cooperating witha scale I. The disk 11)is any movement of either-core unbalances the bridge and causes acurrent flow through the conductor 41 providing ample force torestorethe balance. The two coils of each pair of coil sh and F, f and f, andparticularly of the spools'on which the v'ariouscoils are separatelyformed. With'either core thus floating its tendency to-move into aposition central of the two surrounding coils substantially counterbalnnces itstendency to move under the independent action'of either coilinto a central position thereof.

The invention in its broader aspects, is

' capable of embodiment in apparatus difiering in many of its general'featuresas well as in details from the ap aratus disclosed in Fig. l,and in Figs. 2 an 3 I have illustrated by wayof further example, a formof con nd the disk ID tending to rotate the disk ID d n theclockwisedirectioni the fluid flow struction difiering in numerous respects fromthat shown 1. In 2 the difierenaced apart'slightly as by. meansofaspacerF which may consistof a ring or rings oi insulating material, and 'inpractice may well-be formed by the ends tial pressure device AA,replacing the do vice of the construction first described, comprises aU-shaped container for the mercury or other sealin liquid. The deviceAA.

' The totalpressure in the conduit CA is transmitted to the upper end ofthe tube A which forms an upper end extensionof the leg A of the deviceAA by a pipe D, while a pipe D transmits the lower pressure at thethroat of the Venturi section to the upper end of the leg A of thedevice AA. Advantageously when the fluid flowing through the coir duitCA is steam the device AA is located below the level of the conduit CA,so that the upper portion of the legs A and A, the tube Afand all or themajor portions of the pipes D and D will be filled with water ofcondensation, rather than steam. The ortion A of the device AA issurrounded y-coils F and F as in the construction first described thoughas shown the coil F is placed above the coil F.

In-Fig. 2, GA represents an instrument which may be identical with theinstrument G first described, though as shown itis merely a recordinginstrument without integrating provisions and without the separate indicatingpointer I and-co-oper'ating scale I of the instrumentG. The coilsf and f of the I and F and to the supply conductors 1 and 2 instrumentGA areconnect dto the "coils F as the similarly designated parts areconnected in Fig. 1. Associated with the device AA and instrument GA isan indicating instrument IA comprising a disk ID of aluminum or likeconducting material mounted on a shaft which carries an indicatingpointer I,

rotated. into positions corres onding to the diiierent rates of flow ofthe uid metered by the opposing action on the disk 1]) of electro-'magnets IB and IC. The energizing winds ings z andi'bf the electro-manets 1B, and" 10,. respectively, are 'connecte in parallel-f".with-the'windings f and f of the instrument coils-IE of the twoelectro-magnets 113 an IC are so disposed that the alternating currentflow through the A coil 2' creates a reaction between thedisk ll) andthemagnet IB tending to rotate the disk in the counterclockwise direction,while the creates an interaction etwen the magnet 10 alternate currentener 'zation of the coil z" through the conduit CA increases with aresultant increase in the current flow through the coil 2" and asimultaneous decrease in the amount of current flowing through the coil2', the disk ID and the pointer I are consequently moved in theclockwise direction. To insure a definite position of equilibrium of thepointer I'for given current flows through the coils i and c", thealuminum disk ll) is so shaped that the area of the portion of the diskin inductive relation with the core of the magnet l will diminishrelative to the area of the portion of the disk- ID in inductiverelation with the core of the magnet EB as the disk ID rotates in theclockwise direction and swings the pointer l away from the zero positionof the latter. In the condition shown in Fig. 2, in which the core E isin its middle position and the currents in the coils i and c" are equal,the portions of the disk ID between the poles of the two magnets IE and1C are or" the same area.

The similar responses of the instruments Gel and. IA to changes in theiiuid iiow through the conduit CA. illustrates the fact that anysuitable form of differential volt meter may be em loyed as'theactuating element of the exhioiting instrument, whether that instrumentbe a simple indicator like the instrument iii, a simple recorder likethe instrument GA, or an indicating, recording integrating instrumentlike the instrument G.

A characteristic advantage of the type or" circuit connections employedis that two or more instruments may have their energizing windings f, f2', z" etc, connected in parallel without material effect on oneanother, or on the amount of current flow through the winding 1?, F ofthe difierential pressure device. This facilitates the location indifierent positions of a plurality of difierent exhibiting instrumentsresponsive to the same differential pressure device.

Certain novel characteristics of the manometer and immediatelyassociated parts disclosed but not claimed herein are claimed in mycopending application Serial No. 128,466, filed August 10, 1926, and inmy copending application Serial No. 218,688, filed September 10, 1927 asa division of said application Serial No. 128,466.

While in accordance with the provisions of the statutes, l haveillustrated and described the best form of my invention now known to me,it will be apparent to those skilled in the art that changes may be madein the form of the apparatus disclosed without departing from the spiritof my invention as set torth in the appended claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding use of other features.

Having now described my invention, what I claim as new and desire togacure by Letters Patent, is: i

1. In a flow meter, the combination of a differential pressure-deviceincluding a body of magnetic material adjusted to diti'erent positionsby different pressure differentials impressed on said device, meansincluding a second movable body of magnetic material exhibitingdiiierent rates of flow according to the difi'erent positions of saidsecond body, means comprising a self balancing impedance bridgeincluding a separate pair of stationary coils in inductive relation witheach of said magnetic bodies and means for connecting the two coils ofeach pair to a source of alternating current in such manner relative tothe direction of coil winding that said two coils induce magnetic flowin the same direction through the said body in inductive relationtherewith for causing the movements of the first mentioned body toproduce corresponding movements of said second body.

2. In a flow meter, the combination of a differential pressure deviceincluding a body of magnetic material adjusted to different positions byditierent pressure diiierentials impressed on said device, meansincluding a second movable body of magnetic material exhibitingdifferent rates of flow according to the-different positionsof the saidsecond body, and means comprising an impedance bridge including a pairof end to end coils in which the first mentioned magnetic body isaxially movable, and a second pair of end to end coils energized in thesame direction in which said second body is axially movable for causingthe movements of the first mentioned body to produce correspondingmovements of said second body.

3. in a flow meter, the combination of a difierential pressure deviceincluding a body of magnetic material, a pair of end to end coils inwhich said body is axially movable in response to variations in thedillercntial pressure impressed upon Said device and thereby varies therelative inducta'nces of said coils, a second pair of end to end coils,a second body of magnetic material axially movable in the last mentionedcoils in response to changes in the electric flows therein, exhibitingmechanism operated by said second body, means connecting the two coilsof each end to end pair in series with each other and in parallel withthe other two coils to a source of alternating current so as to energizethe two coils of the second pair in the same direction and a crossconnection between the adjacent ends oi the two coils of each pair andthe corresponding ends of the other two coils.

a. In combination, an inductive electrical winding comprised of twoparts connected in series to a source of alternating current. a body ofhigh magnetic permeability movable to diil'erent positions with respectto said winding in accordance with changes in a quantity to be measured,in such manner as to thereby vary the relative values of the inof saidcoils and thereby vary the inductances ductances of the two parts ofsaid winding and correspondingly vary the relative potenthe two lastmentioned coils act upon the last.

tial drop in said winding parts, and a differential voltmeter comprisingtwo coils, one

: connected across each of said winding parts and a movable elementadjusted to diflferent positions by changes in the relative voltagesimpressed on said coils.

5. In a meter, a pair of end to end coils, a magnetic body adapted to bemoved axially other two coils to a source of alternating current so asto energize the two coils of each pair in the same direction, and across connection netic material, of a pair of in induc: I V

tive' relation with said material and having between the adjacent endsof the two coils of each pair and the corresponding ends of the othertwo coils. f

6. In a flow meter, the combination with a differential pressure devicecomprising a casing, and magnetic material within said casing adjustedto different positions by changes in the pressure diflerential impressedon said device, a pair'of windings external to said casing andininductive relation with said material and having their inductancesrelatively varied by, changes in adjustment of said material, meansadapted to connect said windings in series with one another to a sourceof alternating current, and electro magnetic means for indicatingchanges in adjustment of said material comprising two windings, onehaving its terminals connected to the terminals of one; and the otherhaving its terminals connected to the terminals of the second of the twofirst mentioned 7 The combination with movable mag- 7 their inductancesrelatively varied by changes.

in position ofsaid material, means adapted to 7 connect said 'windingsin. scrim with one another to a source of alternating current, andelectro-magnetic means ,for indicating changes in adjustment of saidmaterial com- 7 slightly spaced apart, one having its terminalsconnected to the tof one, and the other having its terminals connectedto the. terminals or the second of the two first mentioned windings sothat both coils induce 8: The combination with etic mate-' end pair inseries amasserial movable into difierent positions, of a pair ofwindings in inductive relation with said material and having theirinductances.

relatively varied by changes in position of said material, means adaptedto connect said,

windings in series with one another to a source of alternating current,and electromagnetic means for indicating changes in po- A sitions ofsaid material comprising two coils in end to end relation with-oneanother, one havin its terminals connected to the terminals 0 one, andthe other having its terminals connected to the terminals of the secondof the two first mentioned windings, sothat both coils induce magneticflow in the same axial direction at any one instant, and a body ofmagnetic material movable axially in said coils, said coils and bodybeing so relatively arranged that said body tends to assume a positionwhich varies with the position of the first mentioned magnetic material,and from which it may be displaced by a relatively small 'force,'and asa result of any such disv placement creates a relatively large forcetending to move it back toward the first mentioneiposition of said body.

netic material adjusted to different positions by difierent pressuredifierentials impressed on said device, a winding in inductive relationwith saidematerial and comprising two parts, the relative-inductances ofwhich are variedby the osition of said material and, a second windingcomprising two parts inaxial alignment connected to the first mentioned.windingpboth windings being coni prising two coils in end to endrelation and v a fiow meter, the combination of a differential pressuredevice including mag- 10 n. arson. J

